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Gastrulation - Anatomy & Physiology (view source)
Revision as of 15:07, 25 August 2008
, 15:07, 25 August 2008→Gastrulation at the Primitive Streak
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**This defines the posterior of the embryo.
**This defines the posterior of the embryo.
*Eventually, convergence causes cells to be displaced anteriorly. As more cells converge, the primitive streak elongates.
*Eventually, convergence causes cells to be displaced anteriorly. As more cells converge, the primitive streak elongates.
−*Cells in the primitive groove change shape from columnar to wedge shaped, which produces two elevations either side of a groove.
+*Cells in the primitive groove change from columnar to wedge shaped, which produces two elevations either side of a groove.
*Epiblastic cells of the primitive streak begin to ingress ventrally to form the new germ layers.
*Epiblastic cells of the primitive streak begin to ingress ventrally to form the new germ layers.
**As the primitive streak extends into the anterior it enters certain "territories" of the epiblast. These are regions, organised from posterior to anterior, which are destined to become certain germ layers.
**As the primitive streak extends into the anterior it enters certain "territories" of the epiblast. These are regions, organised from posterior to anterior, which are destined to become certain germ layers.